1. Field of the Invention
The present invention relates to a streaming transmission method, which is applied to a streaming transmission system for transmitting data by streaming transmission from one information processing apparatus to other information processing apparatuses connected to the one information processing apparatus through communication network; a streaming transmission system; a data processing apparatus, and a computer program product for operating a general computer system as the data processing apparatus of the present invention.
2. Description of Related Art
In recent years, in a Website, in order to effectively transmit information, a technique for transmitting voice data or animation data by streaming transmission (distribution) is employed. In streaming transmission, since the voice data, animation data or the like to be transmitted from a Web server is reproduced by being sequentially read from a memory of a client computer for receiving data, while being stored therein, voice or a video image can be reproduced in real time, without waiting for a completion of download of all data.
In addition, a VoIP (Voice over IP) technique for transmitting the voice data or the like over the Internet, an Intranet or the like using an IP (Internet Protocol) which is a general protocol has also become widespread. In the VoIP, by dividing digital coded voice data for every definite period of time to packetize it, the voice data is then transmitted to other information processing apparatuses. Other information processing apparatuses which have received the voice data by VoIP reproduce the voice data by sequentially reading it from a memory, while storing it therein, similar to the case of the client computer described above. The voice data can be reproduced in real time between the information processing apparatuses according to such streaming transmission of the data.
Incidentally, the streaming transmission technique is disclosed, for example, in Japanese Patent Application Laid-Open No. 2002-118831 (JP-A, 2002-118831).
However, when the client computer receives the voice data or the animation data by streaming transmission from the Web server, there is a fear that a computer virus program may be simultaneously transmitted in conjunction with the animation data or the like by streaming transmission from a malicious Web server.
When a user receives the data transmitted by streaming transmission, there is no other way but to browse the Websites to judge whether such risk would be included therein or not through intuition, even if the malicious cracker would make the computer virus program mix into the streaming data, it is difficult to ascertain that in advance.
When talking to a third person over the phone using the VoIP, there also exists a fear that the third person may transmit the computer virus program as the streaming data in addition to the voice data. Conventionally, in order to secure security, after making a user enter a user ID and a pass word for authentication prior to a call start, streaming transmission is made to start. However, once the transmission and reception of the streaming data have been started, even if the malicious speaker would transmit the computer virus program instead of the voice data, it is impossible to protect the security from such an illegal act by means of the authentication described above. In the future, it is clear that such harmful effect would become more remarkable as the data transmission from the Web server according to the streaming and the demand of the telephone according to the VoIP increase.